DO NOT MERGE: Fix potential deadlock in Exchange startup/shutdown code

* Move onCreate() and onDestroy() work out of UI thread

Bug: 3512859
Backport of Iad46cc8ce11c842bb23a9bf54cdae1c447b9e7e6

Change-Id: I868f1525db0f8ef3ad2430dd617923cd578cb39c
1 file changed